demandimport: ensure lazyloaderex sets loader attributes (issue6725)

Adds test capturing missed expectation.

hgdemandimport/demandimportpy3.py

@@ -41,6 +41,10 b' class _lazyloaderex(importlib.util.LazyL'
         """Make the module load lazily."""
         with tracing.log('demandimport %s', module):
             if _deactivated or module.__name__ in ignores:
+                # Reset the loader on the module as super() does (issue6725)
+                module.__spec__.loader = self.loader
+                module.__loader__ = self.loader
+
                 self.loader.exec_module(module)
             else:
                 super().exec_module(module)

tests/test-demandimport.py

@@ -234,3 +234,11 b" assert 'ftplib' not in sys.modules"
 zipfileimp = __import__('ftplib', globals(), locals(), ['unknownattr'])
 assert f(zipfileimp) == "<module 'ftplib' from '?'>", f(zipfileimp)
 assert not util.safehasattr(zipfileimp, 'unknownattr')
+
+
+# test deactivation for issue6725
+del sys.modules['telnetlib']
+with demandimport.deactivated():
+    import telnetlib
+assert telnetlib.__loader__ == telnetlib.__spec__.loader
+assert telnetlib.__loader__.get_resource_reader